Orchard Spray Rates
How to Determine the Amount of
Pesticide and Water to Use in Your Orchard

Bulletin 892-01

Calculations for Concentrate Applications,
How much pesticide is needed for a concentrate application?

Introduction to Methods 4 and 5:

Use a pesticide rate per acre customized to your fruit operation, based on tree-row volume.

Method 4: Use a pesticide rate customized to your fruit operation based directly on the tree-row volume method.

When a label states the rate of pesticide per 100 gallons of water, then the rate of pesticide per acre can be customized for your sprayer and your orchard, by following either of two methods based on tree-row volume. With either method, first you need to determine your dilute volume of water per acre, as described previously (pages 4-6). Once you know your dilute volume, then you can determine your pesticide rate per acre either directly by tree-row volume (Method 4) or by the percentage-of-standard method (Method 5). Whether to use Method 4 or Method 5 is just a matter of personal preference; they are both based on the same principle.

Advantage of Methods 4 and 5: Spray costs are reduced by not applying more product than necessary.

Disadvantage of Methods 4 and 5: These are more complicated to calculate. However, most calculations can be done once per year; there is no need to recalculate for every spray.

Recommendation: Method 4 or 5 is best whenever the rate per acre is not provided on the label. In other words, these methods are best whenever Method 1 does not apply.

Simply take your dilute volume of water per acre and multiply it by the dilute rate of pesticide per 100 gallons of water. This is a customized rate, because your dilute volume is based on the size and spacing of your trees.

the dilute rate of pesticide per 100 gallons of water x your dilute volume of water per acre = your customized pesticide rate per acre

For example, for application of Imidan 70WP at a dilute rate of 1 pound per 100 gallons, in an orchard that needs 180 gallons per acre to treat to runoff: take 1 pound per 100 gallons, times 180 gallons per acre, which equals 1.8 pounds. You thus need 1.8 pounds of Imidan 70WP for each acre. You can see that this is much less product than if you had used just the full rate, which is 4 pounds of Imidan per acre.

1 pound 100 gal. water x 180 gal. water acre = 1.8 pounds Imidan per acre

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